Image Digital Watermarking Algorithm Research Based On Alternation Domain

The digital information media makes storage of information becomes more and more convenient. With the development of computer network communication technology, data exchange and transmission become a relatively simple process. Although network and digital bring people great convenience, at the same time intellectual property rights of digital media and digital authentication become more and more prominent. To be the means to solve this problem, digital watermarking is effective. From the 1990s of last century, as an effective means of intellectual property protection and digital multimedia content authentication, digital watermarking technology is a new research field in information security.The digital image is focused in this paper. At first,the background and significance of digital watermarking, the status of domestic and foreign research of digital watermarking and the application fields of digital watermarking are introduced. Then the basic theory of digital watermarking is described in this paper. Typical algorithms of dagital watermarking is described in detail. Based on analysis of the advantages and disadvantages of classical methods, three kinds of image watermark algorithm based on transform domain are proposed, which are detail as follow:1.A fragile watermarking algorithm based on hadamard transform is proposed. In the method, original image is firstly divided into 4×4 blocks, calculate the standard deviation of each block, the fractional part of the standard deviation and a watermarks key are combined as the initial value of logistic maps for the generation of the fragile watermarks. Then the fragile watermark is embedded into the Hadamard transform domain in the DC component. Image authentication have not the original image, Experimental results show that the algorithm is an effective method of identifying images.2. We propose a kind of watermarking algorithm based on hadamard transform and DWT. Firstly the wartermark image is arnold scrambled; then the algorithm makes use of the orthogonality of hadamard matrix to encrypt the watermark image, and with this the the wartermark image is generated.Then original image is divided into blocks,each block of original image is decompose with wavelet transform. Exploiting the excellent properties of the wavelet transform—the time and frequency localization character of wavelet transform, the wartermark image which is transformed by arnold transform and hadamard transform is embeded in the frequency domains of original image. According to the specified threshold the watermarking can be extracted. Experimental results show that this algorithm has no appreciable influence to image appearance and it is robust to geometrical attack and signal manipulations.3.A watermarking algorithm for self-embedding of an image was proposed. The image was divided into small blocks and each block was singular value decomposition. Then the quantization image was obtained by drawing the maximum SVs to be quantized from each block. The binary code of quantization image firstly was scrambled and chaotic encrypted, then which was embedded into LSBs of original image, which were set to zero. The algorithm not only can detect and locate the tampering to image, but also recover the content of the tampered image. Experimental results demonstrate that the locating of tamper can be located accurately and the quality of recovery of damaged image's content was effective.